ShopTalk Forums | Aircooled VW Tech & Restoration Help

Hi, I am planning to build a 1776 for my bus it will be fairly mild with a Engle 100 or 110, 040 heads and 36 IDF carbs.

My concern is the case has 10mm head studs and as we all know, these were superceded with 8mm studs and casesavers by VW. Would the 10mm studs be likely to pull out with the uprated engine. Should I replace them with 8mm studs, if I do this what casesavers do I need to use and should I drill the stud deep at #3, has anyone else done this conversion.

Thanks
Andy.

First, what's the codeletter of the case you plan to use? Most "good" dual-relief cases already have the sunken-stud modification - it significantly reduces the chances of the case ever cracking at the base of #3 and is well worth the extra effort.

Even if you stay with 10mm studs you'll want steel head-stud inserts (those made Timesert would be a good choice, they're the slimmest and cutting the case out for the larger cylinders won't compromise them). Those are m12x1.5, same O.D. as the factory 8mm inserts; both are available in larger sizes as well. The Timeserts require a special stepped drill and broaching tool to install correctly, you may be able to borrow/rent a kit for the job.

OEM stock 8mm studs, even though you torque them to a lower number, reduce the incidence of compression leaks because they maintain a more uniform clamping pressure (since they expand & contract at a rate closer to the rest of the engine) so they would be an upgrade, but they certainly wouldn't be mandatory. And finding good new studs with the same characteristics isn't that easy anymore. Personally I probably wouldn't bother, unless I could find some OEM German studs (IMO good used German are preferable to new Mexican or plain-white-box).

1775 has always been a good "bang-per-buck" displacement, not too big for stock-valve heads or stock heater boxes if the RPM range is kept reasonable. Another viable option is 1835 if you use the "thickwall" 92 from AA which fit the same case register but take heads cut to "94" size.

Are you planning on using a counterweighted crank? With the W-100 it shouldn't be necessary (and the rest of the valvetrain could remain stock). To take advantage of the W-110 you'd want a CW crank, stronger valve springs, and "solid" rocker shafts (the latter are always a worthwhile upgrade IMO). If you're staying with the stock crank, it should be 8-dowelled to the flywheel. Either way, plan on a CrMo glandnut w/oversize washer.

I have just had a look at the case, it is a type3 TO case, I measured the depth of the #3 deep stud, it is 38mm so I guess it is drilled to the correct depth for an 8mm long top stud.

As it happens I have the timesert kit so do you recommend I fit the inserts if I use the 10mm studs, would the studs be likely to pull out of the case with 1776 if I didn't fit the inserts .

My intention is to start with a good 1600 , machine it to fit 90.5 barrels and pistons, change the cam to take advantage of the increased capacity and as necessary fit bolt up rocker shafts and uprated springs. So I will be using the stock crank and rods.

The 1600 I have with 36idfs drives really nicely, it just doesn't have enough power to keep up with modern traffic, I would like to keep the power at low rpms but just increase the top end so I can put my foot down to change lanes if I need to.

Thanks
Andy.

Type I cases can generally be dated by the letter code (or at least grouped by significant characteristics) but with a Type III it's not so simple.
"TO" only tells us that it's 1966 or newer and came equipped with carburetors, which encompasses five different "sub-breeds" of case.
("UO" is `68-up fuel-injected, still four case possibilities)

Generally speaking the significant characteristics - such as alloy, oil-passage and pump stud sizes, single- or dual-relief - are the same as those of a contemporary Type I case. A `66/67 Type III case compares to an ""FO" or "HO" Type I, a `68/`69 to an "H5" (or "B5" from a Type II), a `70 to a "B6", a`71-up w/10mm studs to an "AE", or a `73 w/8mm studs to an "AH"...that's the order of desirability, from lowest to highest, as well - other than the H5/B5 which belong in the scrap barrel.

Because yours has the sunken-stud mod it's probably a `71 or newer dual-relief case and the alloy shouldn't be an issue (should be AS41, look for that cast into the side of the sump). Another good sign is the presence of horizontal ribs cast into the case, like a little washboard, on the angled panel above where a Type I dipstick tube is - those debuted partway into 1971 model-year production
These cases aren't infamous for head stud threads pulling, warping, or cracking like the H5/B5-type were but in deference to their age I still have them inserted, even when building a stocker, as insurance against remorse down the road for trying to save a little money. You don't have to do it, but I strongly recommend it - if you do, be sure to retain the sunken stud and make sure that your drill press bed is level so you don't end up with a "porcupine".

Don't forget the crank/flywheel junction - if you don't 8-dowel, you'll need to possess the restraint to never, ever show off with burnout attempts or even hard launches. Even a relatively mild 1775 is capable of shedding a 4-dowelled flywheel if abused.

Don't over-cam it; with the stock crank you should be shifting by ~5000 RPM so it's pointless to use a cam designed to pull beyond that. Something in the low to mid 230s effective duration (@.050"). Most of these should have entry-level HD singles (Engle W-100 can work with good stock springs). Bugpack 4061-10's a good Bus cam. Don't know if you can still get an Erson E746522 but its 106° LSA enhances low-end torque (doesn't help fuel economy though).

There's a chart at theSamba that you can use to date your engine case by its full number: http://www.thesamba.com/vw/archives/inf ... berst3.php